Implantable medical devices including septum-based indicators

ABSTRACT

A method of making an access port, includes providing a port body defining a fluid cavity, positioning a septum over the fluid cavity, and securing the septum to the port body. The septum includes a lower portion having a first diameter, an upper portion joined to the lower portion at a juncture, the upper portion having a second diameter less than the first diameter at the juncture, and a plurality of palpation features joined to the upper portion. Each of the palpation features includes a first end adjacent a central axis of the septum, and a second end extending radially outward, overlapping the juncture.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No. 14/587,862, filed on Dec. 31, 2014, now U.S. Pat. No. 10,052,471, which is a division of U.S. patent application Ser. No. 12/617,981, filed Nov. 13, 2009, now U.S. Pat. No. 8,932,271, which claims the benefit of U.S. Provisional Patent Application No. 61/114,331, filed Nov. 13, 2008, and titled “Septum-Based Indicators for an Implantable Medical Device,” each of which is incorporated herein by reference in its entirety.

BRIEF SUMMARY

Briefly summarized, embodiments of the present invention are directed to a medical device, such as an access port for providing subcutaneous access to a patient. The access port includes a septum including palpable identification indicia thereon. In particular, the access port in one embodiment includes a body that defines a fluid cavity and a needle-penetrable septum covering the fluid cavity for providing access thereto. The septum defines an outer periphery.

The palpable identification indicia of the septum are included as a plurality of raised palpation features. Each palpation feature includes a portion that extends in a radial direction beyond the outer periphery of the septum. The palpation features are therefore disposed relatively farther away from each other, simplifying palpation and identification thereof after the port has been subcutaneously implanted into a patient. The palpation features can be indicative of an attribute of the port, such as its ability to withstand fluid pressures and flow rates associated with power injection, for instance.

In other embodiments, the size, shape, number, and placement of the palpation features on the septum or other port surface can vary as appreciated by those skilled in the art.

These and other features of embodiments of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of embodiments of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the present disclosure will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. Example embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1A is a perspective view of an implantable port including a septum configured according to one example embodiment;

FIG. 1B is a top view of the port of FIG. 1A;

FIG. 2 is a cross sectional view of the port of FIG. 1B, taken along the line 2-2;

FIG. 3 is a perspective view of the septum included in the port of FIG. 1A;

FIG. 4 is a cross sectional view of the septum of FIG. 3, taken along the line 4-4;

FIG. 5 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 6 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 7 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 8 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 9 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 10 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 11 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 12 is a top view of an implantable port including a septum configured according to one embodiment;

FIG. 13 is an exploded perspective view of an implantable port including a septum configured according to one embodiment;

FIG. 14 is a top view of an implantable port configured according to one embodiment; and

FIGS. 15A and 15B are a top and side view, respectively, of an implantable port configured according to one embodiment.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Reference will now be made to figures wherein like structures will be provided with like reference designations. It is understood that the drawings are diagrammatic and schematic representations of exemplary embodiments of the present invention, and are neither limiting nor necessarily drawn to scale.

FIGS. 1A-15B depict various features of embodiments of the present invention, which are generally directed to medical devices including ports, also referred to herein as access ports, for implantation into the body of a patient. In some situations, it can be desirable to facilitate access to the vasculature of a patient for purposes of blood withdrawal and/or infusions, such as when the patient is ill and may repeatedly undergo such procedures. In one implementation, vascular access is established via a catheter situated within a blood vessel of the patient. A port, subcutaneously implanted in the patient, is placed in fluid communication with the catheter. Accordingly, infusions and blood withdrawals may be made percutaneously via the port, rather than directly through the wall of a blood vessel.

Reference is first made to FIGS. 1A-4, wherein an implantable port 10 is disclosed as configured in accordance with one example embodiment. As shown, the port 10 includes a body, or housing 20, which defines a fluid cavity 30 in communication with a rimmed opening, or aperture 34, on an upper surface of the port. The housing 20 defines a passageway 40 in fluid communication with the fluid cavity 30 into which a stem 31 is disposed, wherein the stem is configured for coupling with a lumen of a catheter so as to provide fluid communication between the catheter and the fluid cavity. In another embodiment, the stem can be integrally formed with the housing.

In the present embodiment, the port 10 includes a septum 50. The septum 50 is coupled with the housing 20 to cover the aperture 34 and the fluid cavity 30 defined by the housing, thus providing selective access to the fluid cavity. In the present embodiment, for example, the septum 50 includes an elastomeric material capable of being punctured by a needle, for example, a Huber needle, and substantially resealing upon removal of the needle. In one embodiment, the septum 50 includes silicone, though other materials can also be employed. In the illustrated embodiment, the port housing 20 includes a metallic material such as stainless steel or titanium, and the septum 50 is secured in place in the housing by a metallic retaining ring 24 that is press fit into the housing, as shown in FIG. 2. As will be seen below, the principles of the present disclosure can be employed with other port materials and configurations. These and other configurations are therefore contemplated.

The port 10 is configured to be implanted subcutaneously within a patient and operably connected to a catheter that, in turn, is disposed within a vein or other vessel. Accordingly, when the catheter is coupled with the stem 31 of the port 10, fluid communication can be established with the vessel via the fluid cavity 30, such as by an infusion needle inserted through the septum 50 of the port. A plurality of suture holes 42 can be included in the housing 20 so as to facilitate securement of the port 10 to the tissue of the patient when implanted.

The septum 50 in the present embodiment is defined by a body 52 including an upper body portion 52A that is generally exposed through the aperture 34 of the port 10 and a lower body portion 52B that is generally included within the interior of the port housing 20. The upper body portion 52A and lower body portion 52B define a juncture 53. The upper body portion 52A includes a top surface 56 and an outer periphery 54. Though the present embodiments deal particularly with the outer periphery 54, i.e., a first outer periphery of the septum upper body portion 52A, the lower body portion 52B can be considered to define a second outer periphery including a relatively larger diameter than that of the first outer periphery.

In the present embodiment the periphery 54 of the upper body portion 52A of the septum 50 is circular to match the circular aperture 34, but in other embodiments it is appreciated that the outer periphery of the septum could define other shapes, including triangular, square, polygonal, other geometric shapes, etc. To the extent that the periphery of the septum defines other shapes, in some embodiments the shape of the aperture can also be modified to correspond in shape to that of the septum.

According to the present embodiment, a plurality of palpation features is included on the septum 50. As shown in FIGS. 1A-4, the palpation features are included as three protrusions 60 that extend from a surface of the septum 50. The three protrusions 60 are equidistantly spaced at substantially regular intervals around an outer portion of the septum 50 as to define end points, or vertices, of an imaginary triangle such as an equilateral triangle in the present embodiment. As best seen in FIG. 1B, the protrusions 60 generally align with the vertices of the generally triangularly-shaped port housing 20. The protrusions 60 extend upward from the generally flat septum top surface 56 such that the protrusions provide surface features to a top profile of the port 10 from the perspective shown in FIG. 2.

Note that, though three are used here, fewer or more palpable protrusions can be included on the septum top surface. Indeed, only one protrusion can be employed if desired. Also, though the port shown here is a port with a singular fluid cavity, multi-lumen ports including a plurality of fluid cavities and corresponding septa can include the palpation features discussed herein. The spacing, shape, and size of the palpation features can vary in a number of ways, some of which are described further below.

As best seen in FIG. 1B, the protrusions 60 are shaped and positioned as to include a radially outward portion 62 that radially extends past the circular outer periphery 54 of the septum 50. Thus, the radially outward portion 62 of each protrusion 60 extends beyond, or overlaps, the aperture 34 and thus extends over a portion of the retaining ring 24. The radially outward portion 62 of each protrusion 60 includes a bottom surface 55 extending angularly away from the upper body portion 52A of the septum 50, as shown in FIG. 4.

The overlapping aspect of the protrusions 60 causes a center point of each protrusion to be disposed relatively farther away from the other protrusions than if the protrusions were confined within the bounds defined by the septum outer periphery 54. This in turn enables the protrusions to be more easily palpated and identified by a clinician performing the palpation for an implanted port than if the protrusions were closer set. Thus, the tactile acuity of the clinician palpating the port 10 is preserved without increasing the size of either the septum or its protrusions. Desire for increased tactile acuity has increased in recent years in light of the trend toward a reduction in size of manufactured ports, and by extension, septum size.

In greater detail, FIG. 4 shows one of the protrusions 60 of the septum 50 in cross section, wherein a notch 64 is defined by virtue of the overlapping nature of the protrusion. The notch 64 enables the protrusion to extend over the edge of the aperture 34, defined in this embodiment by the retaining ring 24, without interfering with the retaining ring. Of course, the size and shape of the notch and protrusion can be modified to adapt to a particular port configuration.

The protrusions 60 in the present embodiment are oblong-shaped, generally resembling a seed or tear drop shape, and include a smoothly contoured surface, as best seen in FIGS. 1B and 3. The smooth contour of the protrusions 60 assists in reducing tissue irritation when the port 10 is implanted in the patient. In the present embodiment where the septum 50 generally defines a disc-like shape including an outer periphery diameter of about 0.42 inch (indicated at X₁ on FIG. 4), the protrusions 60 axially extend a distance of about 0.046 inch above the top surface 56 of the septum body 52 (indicated at Y on FIG. 4) and about 0.055 inch radially beyond the periphery 54 (indicated at X2 on FIG. 4), though other size dimensions are of course possible. The protrusions 60 are integrally formed with the septum 50 in the present embodiment, but could be separately formed and attached to the septum in another embodiment. Note that the shapes of the protrusions can be shaped in other ways, as will be seen further below. Note further that each protrusion on the septum can include a different shape with respect to the other protrusions, if desired.

In one embodiment, the palpation features, i.e., protrusions 60 of the septum 50, can permit a clinician to properly identify a predetermined attribute or characteristic of the port 10. The attribute of the port 10 in one embodiment is the suitability of the port to withstand relatively high fluid flow and/or fluid pressure rates therethrough, commonly referred to as “power injection.” Such high pressure and flow rates are typically associated with power injection of fluids through the port during relatively demanding procedures (e.g., computed tomography, or “CT,” scans), in which contrast media is rapidly infused through the port and connected catheter and into a vascular system. For instance, in one embodiment power injection includes fluid infusion by a power injection machine producing fluid pressures of up to about 325 psi, resulting in fluid pressures in the port 10 between about 50 and about 90 psi and fluid flow through the port at a rate between about two and about five milliliters per second. Other flow rates and fluid pressures are, of course, possible.

During power injection, a needle can be inserted in a septum of the port and connected to a power injection machine, which can introduce contrast media through the port at a relatively high flow rate, as detailed above. Certain ports may not be able to withstand pressures corresponding to high flow rates during power injection. Accordingly, it is often necessary to determine whether an implanted port is compatible for power injection.

The protrusions 60 enable identification of a port as power injectable, in one embodiment. In particular, after subcutaneous implantation of the port 10 in a patient, a clinician cannot visually observe the port to determine whether it is suitable for power injection. With a port 10 configured as shown in FIGS. 1A-4, the clinician can feel or palpate the three protrusions 60 through the skin to determine that the port is suitable for power injection. In addition, other information regarding the port 10 can be gathered by palpation, including the general orientation of the port, location the septum 50, etc.

In addition to its suitability for power injection, in other embodiments other predetermined attributes or characteristics of the port can be indicated by the protrusions described herein. Such attributes include, for example, the type of catheter to which the port is connected, e.g., whether the catheter distal tip is open-ended or includes distal valve, the type of material from which the port is constructed, etc. Such ability to determine the predetermined characteristic(s) of the port is useful for ports of all types, including those made from radio-translucent materials, which are not sufficiently imaged radiographically.

As already described, the protrusions 60 in FIGS. 1A-4 are tear drop-shaped to provide a smooth contour surface and to avoid irritating body tissue proximate the port implanted location. In other embodiments, though, the shape, size, number, and placement of the palpation features can be modified from what is explicitly shown and described herein in order to suit a particular need. FIGS. 5-12 give several examples of different possible protrusion configurations for the septum 50 of the port 10. FIG. 5 shows overlapping protrusions 160 defining a flat cylindrical shape. FIG. 6 depicts protrusions 260 defining flat cylindrical shapes similar to those shown in FIG. 5, wherein the protrusions 260 overlap the aperture 34 a relatively more than the protrusions 160 of FIG. 5.

FIGS. 7 and 8 depict protrusions 360 and 460 that define oblong and roughly conical shapes, respectively, while FIGS. 9 and 10 respectively depict semi-spherical protrusions 560 and 660. FIGS. 11 and 12 show relatively thin protrusions 760 and 860 disposed with their long axes extending tangentially to the septum outer periphery 54. Note that the outer periphery 54 of the septum 50 in FIG. 12 generally defines a triangular shape.

As described above, the principles of the present disclosure can be applied to ports from a variety of materials. FIG. 13 gives one example of this, wherein a port 1010 is shown including a cap 1014 and a base 1016, both formed from an engineering plastic material, such as Polyoxymethylene (“POM”), also known as an acetal resin, or other suitable material. The septum 50 including the protrusions 60 is sandwiched between the cap 1014 and base 1016 so as to be captured therebetween when the cap and base are mated together and such that the protrusions overlap past an aperture 1034 defined by the cap 1014. Note that in the illustrated embodiment, four overlapping protrusions are included on the septum 50, in contrast to embodiments described earlier. Suture plugs 1022 and a stem 1031 are also included with the port 1010.

Palpation features can be included on the port in other configurations, as shown in FIGS. 14-15B. In FIG. 14, a plurality of protrusions 962 is included on the housing 20 of the port 10. The protrusions 962 can be hard or resilient and are spaced so as to enable palpation of the port 10 when subcutaneously implanted. The protrusions 962 can be adhered to the port housing surface 20 via an adhesive, can be inserted into corresponding holes defined in the housing, or can be included in other suitable ways. Note that, as before, the size, shape, number, and configuration of the protrusions can vary from what is explicitly shown here.

FIGS. 15A and 15B show a plurality of protrusions 1062 inserted into the suture holes 42 of the port housing 20. The protrusions 1062 are resilient and extend a predetermined distance above a top surface of the port 10 so as to enable palpation thereof when the port is implanted. The protrusions 1062 are inserted and secured in the suture holes 42 via a friction fit, mechanical capture, or other suitable method. Of course, the number, size, position, and shape of both the suture holes and corresponding protrusions can vary from what is explicitly described herein.

The number, size, position, and shape of the palpation features can be modified while residing within the scope of embodiments of the present invention. In addition to the above embodiments, it is appreciated, for example, that the protrusions can define patterns other than equilateral triangles, including acute triangles, obtuse triangles, squares, etc. Additionally, one, two, three, four, five, or more protrusions could be used. In one embodiment, the port includes two or more septa with protrusions extending from each. The protrusions can define a variety of different shapes, and may be sized differently. Indeed, the protrusions can include configurations such as those shown and described in U.S. Pat. No. 8,177,762, which is incorporated herein by reference in its entirety. Thus, the foregoing examples are merely illustrative in nature.

Embodiments of the invention may be embodied in other specific forms without departing from the spirit of the present disclosure. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the embodiments is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A method of making an access port, comprising: providing a port body defining a fluid cavity; positioning a septum over the fluid cavity, the septum comprising: a lower portion having a first diameter; an upper portion joined to the lower portion at a juncture, the upper portion having a second diameter less than the first diameter at the juncture; and a plurality of palpation features joined to the upper portion, each of the palpation features including a first end adjacent a central axis of the septum, and a second end extending radially outward, overlapping the juncture, the second end having a bottom surface extending angularly away from the upper portion; and securing the septum to the port body.
 2. The method according to claim 1, wherein the securing step includes press-fitting a retaining ring over the septum and in contact with the lower portion and upper portion thereof.
 3. The method according to claim 2, wherein the port body and the retaining ring are made of a metal material.
 4. The method according to claim 1, wherein the port body comprises a port base, and wherein the securing step includes positioning a port cap over the port base and the septum.
 5. The method according to claim 4, wherein the port cap includes a central opening defining a perimeter, the second end of each of the palpation features overlapping the perimeter after the positioning step.
 6. The method according to claim 1, wherein the plurality of palpation features includes three equidistantly spaced protrusions.
 7. The method according to claim 6, wherein each of the three equidistantly spaced protrusions is tear-shaped.
 8. The method according to claim 1, wherein the plurality of palpation features are designed to indicate an attribute of the access port when palpated following subcutaneous implantation of the access port.
 9. The method according to claim 8, wherein the attribute of the access port is a capability to support fluid flow therethrough at a rate of at least five milliliters per second.
 10. The method according to claim 8, wherein the attribute of the access port is suitability for power injection.
 11. The method according to claim 1, wherein each of the plurality of palpation features have a shape selected from the group consisting of tear-shaped, triangular, semi-spherical, round, elongate, and oblong. 